ARCHITECTURAL MODELS: CONSERVATION APPROACH AND DECISION-MAKING TREATMENT
TWO CASE STUDIES IN WOODPULP CARDBOARD AND EXPANDED POLYSTYRENE
Marta Sorrentino*, Paola Iazurlo**, Bruno Mazzone***, Monica Pignatti Morano****
*Art conservator freelance, [email protected]
** Paintings conservator, Istituto Superiore per la Conservazione e il Restauro, [email protected]
*** Architect, Istituto Superiore per la Conservazione e il Restauro, [email protected]
****Historian of art, Ministry of Culture MIBACT, [email protected]
ABSTRACT
The paper focuses on the study of contemporary architectural models, their constitutive process and the related conservation problems, in order to identify an appropriate method of intervention, which takes into
account their multifaceted nature. The maquette, traditionally associated with preparatory works, has since the last decades moves from architectural firm to museums, often acquiring a specific self-representative
character in accordance to the concept of cultural assets. Modern architecture places traditional materials side by side with new products from the industrial world, chosen for their low costs, ease of operation and
evocative power. This also occurs for maquettes, where woodpulp cardboard or expanded polystyrene sheets frequently are used. The multifaceted nature and materials which make up the contemporary maquette
imposes a reflection on a proposal for a conservation procedure. A questionnaire on the conservation of architectural models has shown different positions on the conservation approach and the background of the
professionals involves in the restoration work highlighting the current difficulty of defining the nature of the maquette. For this purpose, categories of specific historical-aesthetic value are given for this type of
artifacts to provide an instrument for identifying the multifaceted nature of the maquette, and defining an appropriate conservation approach.
CHARACTERISTIC AND PROPERTIES OF POLYSTYRENE
Thermoplastic polymer obtained by styrene polymerization
Tg 80°
Good dimensional stability
Low specific weight
Non-hygroscopic
Good resistance to: alkali, diluted acids, saline solutions
Sensitive to hydrocarbons with a high percentage of aromatic components
Soluble in ketone and chlorinated solvents
Biological, thermic and photo-oxidation degradation
EXPANDED EXTRUDED POLYSTYRENE -XPS EXPANDED SINTERED POLYSTYRENE -EPS
Open Cells: High Evaporation Rate
(Chlorofluorocarbons and Hydrochlorofluorocarbons)Closed Cells: Low Evaporation Rate (Pentane)
Greater density Lesser density
Compact and finished appearance Soft when touching, minor compactness
Porous and electrostatic material: favours penetration
of dust and can convey liquids
Ensemble of the more delicate polystyrene
spheres, adhesion is easily lost
MATERIAL AND EXECUTIVE TECHNIQUE OF CONTEMPORARY ARCHITECTURAL MODELS
The execution techniques of contemporary architectural models are essentially divided into two
categories. Firstly, traditional techniques, ranging from home improvement tools used for the architect's
rapid studies to the modeller’s specialized constructive system with customized tools for specific
processing of plastics (1960 ca.). Secondly, Rapid Prototyping Techniques (1980 ca.), which use 3D
machines capable of creating analogue models with complex geometries.
The two studied models from MAXXI (National Museum of XXI Century Arts, Rome) both belong to the
first category.
The model Casa unifamiliare a Palazzolo Acreide (Siracusa) by Francesco Venezia (1988-89’) was
made using a traditional technique, brought up to date through the use of industrial materials such as
cardboard sheets (moulded and glued together with vinyl glue) and "bricks" of sintered expanded
polystyrene foam (EPS) (Figs 1-4).
Even more innovative is the expanded polystyrene model of the Complesso residenziale IACP a
Corviale, designed by Mario Fiorentino (1972-74’). The model was derived from a single block of
extruded polystyrene foam (XPS), on which the planimetric design was drawn and shaped by means of
a pantograph. The different elements of the maquette were outlined with a machine made of a metal
wire heated by electrical resistance and assembled mostly by joint and inlay. All of this is standing on a
supporting structure consisting of a sheet of expanded sintered polystyrene (EPS). The composition
alternates the color values of white and blue and in the glossy and opaque effects depending on the
presence or absence of the pictorial film (Figs. 5-7).
The research on these models has provided understanding of how architects’ technical and material
are governed not only by costs and ease of operation but also for its evocative and expressive power.
THE MUSEALIZATION OF ARCHITECTURAL MODELS
Traditionally associated with preparatory works, the maquette moves from the architect’s studio to the
museum.
What changes?
• The birth of new collection and museum sectors (21st Century)
• New reflections on categories of cultural assets in need of protection initiatives (the end of 20st
Century)
• Extension of the concept of cultural assets in the normative field
• The subsequent acceptance of historical-aesthetic value
The analysis on the polyvalent nature of architectural modes has highlighted the functional and
conceptual role of this object within the design stage and the current historical- aesthetic meaning.
In order to better understand the value of the maquette in the museum collection a "Questionnaire on
the Conservation of Architectural Models" was created, sent to four Italian and foreign museums
investigating the conservative procedure used for cataloging, archiving, displaying and preserving
architectural models.
From the answers obtained, a variety of conservative approaches emerged due to the current
difficulty in defining the nature of the maquette. Hence, the need to develop a proposal for a specific
conservation protocol (Table 3) in order to establish with certainty the maquette’s current historical-
aesthetic meaning and the professional profile of the person in charge of restoration intervention.
The conferral of cultural significance represents the first step to plan proper preservation of any object
according to the principles of modern restoration theory. In this regard, four categories of historical-
aesthetic value specific to this type of artefacts are identified (Table 4).
CONSERVATION PROTOCOL OF ARCHITECTURAL MODELS
A. RECOGNITION OF HISTORICAL-
AESTHETIC VALUE
B. MUSEUM PREVENTION PLAN: PRECAUTIONARY
AND PROGRAMMED CONSERVATION
1. Museum purchase 1. 1. Localisation and Stocktaking
2. 2.Form for conservation and environmental issues
3. 3.Conservation and restoration treatment
4. 4. Exhibition
5. 5. Packing and Transport
HISTORICAL-AESTHETIC VALUE CATEGORIES IN ARCHITECTURAL MODELS
Iconic: the value derives from the representativeness, correspondence and verisimilitude of the
architectural design expressed both in the writings (reports, drawings) and in the building.
Authorative: the recognition of the author and the technique of execution of the model independently
from what has been built, provides the possibility to trace the characteristics of a unique style
Technical-design: the recognition of the role of the model in the specific design of the architect in order
to understand the technical and material choices (study or presentation model)
Historical: value concerning future critique that the model has had as a result of its realization
(participation in exhibitions and publications)
CONCLUSIONS
A specific conservation plan for these architectural models represents the direct consequence of a
careful evaluation of the value (functional, conceptual and historical-aesthetical) of the maquette
and its technical and material peculiarities.
FUTURE TALKS 017 - The silver edition - VISIONS. INNOVATION IN TECHNOLOGY AND CONSERVATION OF THE MODERN
October 11/13 2017, Die Neue Sammlung - The Design Museum
EXPANDED POLYSTYRENE: XPS AND EPS
The presence of expanded polystyrene, found in both case studies, both in its extruded (XPS) and
sintered (EPS) form, has allowed to deepen the research on this material, highlighting its
technological characteristics and that of decay (Tab. 1).
The expanded polystyrene is produced industrially both in the "sintered" (EPS) form and in its
"extruded" form (XPS). The two products have the same chemical characteristics but different
mechanical properties which depend on the different production processes (Figs. 8-9 and Tab. 2 ).
Figs. 6-7 The model Complesso residenziale IACP a Corviale (Roma),1972-74’ after its restoration and IR transradiance..
Figs. 1-4 The model Casa unifamiliare a Palazzolo Acreide (Siracusa), 1988-89’ before its restoration front view, the polystyrene
supporting structure (EPS), top view. Fig. 5 The model Complesso residenziale IACP a Corviale (Roma),1972-74’, portable digital
microscope (DinoLite) image at low and high magnification. The prolonged transfer of heat to the cutting tool and the different extrusion
direction of the material (XPS) shows a lengthening cell structure.
Tab. 1 Characteristic and properties of polystyrene
Tab 2: Comparison of characteristics and properties of expanded sintering polystyrene (EPS) and
extruded polystyrene (XPS)
Tab. 3 Conservation protocol of architectural models
Tab. 4 Historical-aesthetic value categories in architectural models
Fig. 8-9 The expanded extruded polystyrene (XPS) on left and expanded sintering polystyrene (EPS) on rightFig. 1 Fig. 2
Fig. 3 Fig. 4 Fig. 5
Fig. 6 Fig. 7